Increase In Evapotranspiration Research Articles

The Hydrological Balance in Micro-Watersheds Is Affected by Climate Change and Land Use Changes

Temperate forests are key to the balance and provision of hydrological and environmental services. Currently, these forests are subject to human alterations as well as to the effects of global change, including warming, variability, deforestation, and forest fires. As a consequence, the hydrological balance has been modified. The present study simulates the effects of climate change and land use change on the hydrological balance of micro-watersheds in Mexico using the hydrological model Water Evaluation and Planning (WEAP). The land use change between 1995 and 2021 was estimated to establish a baseline. Climate scenario SSP585 was projected using three global models, MPI-ESM1-2-LR, HadGEM3-GC31-LL, and CNRM-CM6-1 by the 2081–2100 horizon, along with two scenarios of land use change: one with forest permanence and another with loss of forest cover and increased forest fires. Results indicate that future climatic conditions will modify the hydrological balance at the microbasin level. Even with positive conditions of forest permanence, increases in surface runoff of 124% (CNRM), 35% (HadGEM3), and 13% (MPI) are expected. The projections of coverage loss and fires showed surface runoff increases of 338% (CNRM), 188% (HadGEM3), and 143% (MPI). In the high areas of the microbasins where temperate forest predominates, climatic variations could be contained. If the forest is conserved, surface runoff decreases by −70% (CNRM), −87% (HadGEM3), and −89% (MPI). Likewise, the moisture in the soil increases. In areas with temperate forests, there will be modifications of the hydrological balance mainly due to the increase in evapotranspiration (due to the increase in temperature and precipitation). This will cause a significant decrease in flow and interflow. The alteration of these flows will decrease water availability in soil for infiltration. It is expected that the availability of hydrological and environmental services will be compromised in the entire study area due to climate change.

Impacts of vegetation restoration on water resources and carbon sequestration in the mountainous area of Haihe River basin, China

The mountainous region of the Haihe River basin (MHRB) plays an important role in the water resource supply of its nearby mega-cities, including Beijing and Tianjin, and large areas of cropland. With the implementation of afforestation projects in recent decades, vegetation and carbon (C) uptake have greatly increased in the MHRB. In addition, the annual runoff has significantly declined, threatening regional water security. The trade-off relationship between water yield and C uptake in the MHRB remains unknown. This study employed a biogeochemical model (Biome-BGC) to simulate the natural vegetation dynamics and gross primary productivity (GPP) during 1982–2019 driven by climate forcing. A distributed hydrological model (geomorphology-based hydrological model, GBHM) was adopted to assess the impact of vegetation restoration on the hydrological processes. The results indicated that the leaf area index in the MHRB increased significantly (P < 0.01) during 1982–2019, which led to evapotranspiration increase and runoff (R) reduction. Under the influence of vegetation restoration, both the GPP and the water use efficiency (WUE) increased significantly in the MHRB during 2000–2019, however, the improvement of WUE decreased with the aridity index increasing. Our results showed that vegetation restoration can improve C sequestration efficiency in the MHRB and that the trade-off between water yield and C sequestration should be considered in planning ecological projects to achieve C neutrality.

An integrated approach of remote sensing and geospatial analysis for modeling and predicting the impacts of climate change on food security

The agriculture sector provides the majority of food supplies, ensures food security, and promotes sustainable development. Due to recent climate changes as well as trends in human population growth and environmental degradation, the need for timely agricultural information continues to rise. This study analyzes and predicts the impacts of climate change on food security (FS). For 2002–2021, Landsat, MODIS satellite images and predisposing variables (land surface temperature (LST), evapotranspiration, precipitation, sunny days, cloud ratio, soil salinity, soil moisture, groundwater quality, soil types, digital elevation model, slope, and aspect) were used. First, we used a deep learning convolutional neural network (DL-CNN) based on the Google Earth Engine (GEE) to detect agricultural land (AL). A remote sensing-based approach combined with the analytical network process (ANP) model was used to identify frost-affected areas. We then analyzed the relationship between climatic, geospatial, and topographical variables and AL and frost-affected areas. We found negative correlations of − 0.80, − 0.58, − 0.43, and − 0.45 between AL and LST, evapotranspiration, cloud ratio, and soil salinity, respectively. There is a positive correlation between AL and precipitation, sunny days, soil moisture, and groundwater quality of 0.39, 0.25, 0.21, and 0.77, respectively. The correlation between frost-affected areas and LST, evapotranspiration, cloud ratio, elevation, slope, and aspect are 0.55, 0.40, 0.52, 0.35, 0.45, and 0.39. Frost-affected areas have negative correlations with precipitation, sunny day, and soil moisture of − 0.68, − 0.23, and − 0.38, respectively. Our findings show that the increase in LST, evapotranspiration, cloud ratio, and soil salinity is associated with the decrease in AL. Additionally, AL decreases with a decreasing in precipitation, sunny days, soil moisture, and groundwater quality. It was also found that as LST, evapotranspiration, cloud ratio, elevation, slope, and aspect increase, frost-affected areas increase as well. Furthermore, frost-affected areas increase when precipitation, sunny days, and soil moisture decrease. Finally, we predicted the FS threat for 2030, 2040, 2050, and 2060 using the CA–Markov method. According to the results, the AL will decrease by 0.36% from 2030 to 2060. Between 2030 and 2060, however, the area with very high frost-affected will increase by about 10.64%. In sum, this study accentuates the critical impacts of climate change on the FS in the region. Our findings and proposed methods could be helpful for researchers to model and quantify the climate change impacts on the FS in different regions and periods.

Trend and spatial-temporal variation of drought characteristics over equatorial East Africa during the last 120 years

Centennial drought characteristics in Equatorial East Africa (EEA) is investigated using the Standardized Precipitation Evapotranspiration Index (SPEI) derived from the Climatic Research Unit (CRU) dataset. The spatial pattern of drought distribution, as well as drought duration, intensity and frequency, are analyzed for SPEI at a 3-month timescale for March-April-May (MAM) season. Rotated Empirical Orthogonal Function (REOF), Mann-Kendall method (MK), and wavelet analyses are used to study drought’s spatial pattern, trend, and periodicity. The result of the principal component analysis returned six homogenous drought sub-regions. A low drought frequency characterizes EEA (&amp;lt;20%). The drought in the MAM season lasts between 2.2 and 2.8 months. Overall, the result showed a weak long-term drying trend for most parts of EEA that were significant in some sub-regions and insignificant in others. An increase in drought areal extent after the 1980s could be ascribed to the increase in potential evapotranspiration (PET) and is consistent with the negative trend in SPEI value over the six sub-regions. The apparent increase is mainly attributed to the increase in moderate and severe droughts area rather than extreme drought areas. The spectral analysis further reveals that inter-annual drought variability with periodicities less than 8 years dominates in all sub-regions of Equatorial East Africa, which is associated with the critical role of El-Niño in driving the drought variations in EEA.

Hydrological sustainability of in-pit reclaimed oil sands landforms under climate change

Development of robust reclamation designs would require understanding the relative effects of climate change on the water budget of reclaimed Athabasca oil sands landforms (Alberta, Canada). A surplus water budget is critical to sustain pit lakes and periodically freshen localized surface water ponds within the closure landscape. In this study, four hypothetical future climate scenarios were developed from statistically downscaled RCP2.6 and RCP8.5 climate projections and used in a hydrological model to investigate the potential effects of climate change on the water budget of an in-pit reclaimed oil sands mine landform. The four scenarios allowed the assessment of climate change effects for endpoints that bracket a range of future climate conditions on the water balance of the landform. Surface water and groundwater flow and chloride transport were simulated for the 2024–2100 period using daily climate forcing and the results were compared with equivalent responses under historical climate (1944–2020). The results suggest that the hydrological behavior under historical and RCP2.6 scenarios is similar. The climatic water deficit (potential evapotranspiration exceeding precipitation) will rise significantly under the RCP8.5 scenario. However, the modeling suggests that the water budget of the landform will not be too different from the early 21st century prolonged dry climate period. The chloride released from the landform under the different projected and historical climate scenarios also remained similar. Although evapotranspiration increases and leads to relatively drier conditions, a modest increase in precipitation helps maintain a surplus water budget in most years. The results demonstrate that incorporating future climate projections into water balance analyses is crucial to understand the potential reductions in runoff depths.

Stem growth of Amazonian species is driven by intra-annual variability in rainfall, vapor pressure and evapotranspiration

Intra-annual distribution of precipitation in central Amazonia often leads to a short mild dry season and an increase in irradiance, temperature, and vapor pressure deficit; however, the accurate effect of intra-annual microclimatic variability on stem growth is still under investigation. The objective of this study was to determine how stem growth responds to monthly variations in microclimatic factors in the central Amazon. During five years (2008-2012) we measured diameter stem growth of 109 trees (26 species) and used principal component regression to evaluate the effect of microclimatic variability on stem growth in diameter. We found that the mean stem growth in diameter across species increased in response to an increase in rainfall and reference evapotranspiration, but it decreased with a rise in mean and minimum vapor pressure deficit. A contribution of this study is to show that even when irradiance and temperature had no significant effect on stem growth, small changes in vapor pressure deficit significantly affect stem growth. If the dry season becomes longer, as predicted by models, trees currently more sensitive to microclimatic variability associated with droughts would be the most affected by climate changes.

Fate of nutrients and trace contaminants in a large shallow soda lake. Spatial gradients and underlying processes from the tributary river to the reed belt.

Shallow lakes provide a multitude of ecosystem functions, but they are particularly vulnerable to natural and anthropogenic disturbances. Understanding the driving factors determining the fate and spatial distribution of nutrients and pollutants in such systems is fundamental to assess the impact of ongoing or future external pressures endangering their ecological integrity. This study investigates the fate of trace contaminants transported into the large shallow Lake Neusiedl, including contaminants representative of different patterns of sources and emission pathways and of environmental behavior, namely metals, pharmaceuticals, an artificial sweetener and perfluoroalkyl substances. Further, it examines the horizontal spatial distribution of nutrients, ions and physico-chemical parameters with an unprecedented detailed focus on the internal variability within the large reed belt. As described in the past e.g. for chloride, evaporation was identified as the process leading to a substantial concentration enrichment of the industrial chemical PFOA and the sweetener acesulfame K from the tributary river into the open lake. This is particularly relevant in view of the predicted future increase of evapotranspiration due to climate change. In contrast, the observed loss of diclofenac, but also of PFOS and carbamazepine suggests that the well-mixed, humic-rich and alkaline Lake Neusiedl offers favorable conditions for the photodegradation of otherwise very persistent chemicals. Another important finding, in the context of possible modifications in lake water levels due to climate change, is the fundamental role played by the connectivity between open lake and reed belt but also by the presence and characteristics of inner water areas within the reed belt region in determining the hydrochemistry of the lake system. By revealing systematic spatial patterns and by focusing on the underlying factors and processes, the understanding offered by this study is of high value for the conservation of shallow lakes.

Reversal of soil moisture constraint on vegetation growth in North China

The response of vegetation growth to soil moisture varies greatly from space and time under climate change and anthropogenic activities. As an important grain producer in China, the vegetation growth and grain production of North China are constrained by the region's water resources. With the significant increase in vegetation greenness in North China over the last 40 years, it is essential to explore the changes in soil moisture constraints on vegetation growth to water management. However, to what degree vegetation growth responds to soil moisture and how the response varies spatiotemporally in North China remain unclear. In this study, the response patterns of vegetation growth to soil moisture at different depths and the spatiotemporal trend patterns of their relationships were explored thoroughly based on long time series remote sensing data in North China over the past 40 years. The results showed that compared to forests, the growth of grasslands and crops with one maturity per year and two maturity per year in North China was more constrained by soil moisture. Due to the combined effects of climatic conditions and human activities, vegetation growth in North China has been significantly less constrained by soil moisture over the last 40 years. This was especially seen in one maturity per year crop and natural vegetation in Shanxi and central Shandong. However, with the significant increase in temperature, potential evapotranspiration and water demand of the crop, the moisture constraints on vegetation growth in North China have begun to show an increasing trend since the early 2000s, especially for irrigated crop in central and southern North China. These findings highlight a comprehensive understanding of the vegetation response to soil moisture from the time-varying perspective and provide a theoretical basis for water management and appropriate planning of agricultural water use in North China.

Insights into runoff changes in the source region of Yellow River under frozen ground degradation

The source region of the Yellow River (SRYR) in the northeastern Tibetan Plateau is critical for supplying water resources to downstream areas. However, streamflow in the SRYR declined despite a slight increase in precipitation during the past few decades. The SRYR experienced significant frozen ground degradation with climate warming, but how frozen ground degradation influences runoff remains unclear. This study investigated the changes of the precipitation-runoff relationship using the double-mass curve method and examined the impact of long-term spatiotemporal changes in frozen ground on the water balance components using the geomorphology-based eco-hydrological model (GBEHM). The results showed that the precipitation-runoff relationship changed significantly since 1989 in the SRYR from 1960 to 2019. In the same period, the areal mean value of the maximum thickness of seasonally frozen ground (MTSFG) decreased by 0.10 m/10a and the areal mean active layer thickness (ALT) of permafrost increased by 0.06 m/10a. Besides, 21.0 % of the entire SRYR has degraded from permafrost to seasonally frozen ground (SFG). Runoff decreased mainly in the region with elevation below 4200 m, where the evapotranspiration increase exceeded the precipitation increase. Frozen ground degradation significantly altered the hydrological processes, which is reflected by the increased subsurface runoff and the decreased surface runoff. The total water storage increased by 2.9 mm/a in the permafrost region due to the increase in active layer thickness and by 5.7 mm/a in the degradation region where permafrost completely thawed during 1960–2019. The runoff seasonality was also altered, being indicated as an increase in winter runoff. These findings help provide a better understanding of the runoff change under climate warming in permafrost-affected regions and provide insights into future water resources management in the Yellow River basin under the climate warming.

Variation in the hydrological cycle in the Three-River Headwaters Region based on multi-source data

The hydrological processes in the Three-River Headwaters Region (TRHR), which is located in the Qinghai-Tibetan Plateau and includes the Yangtze River Headwater Region (YARHR), the Yellow River Headwater Region (YERHR), and the Lantsang River Headwater Region (LARHR), have changed under climate warming. Based on multi-source data, the spatial and temporal changes in precipitation, evapotranspiration, soil water storage, glacier melt, snowmelt and runoff in the Three-River Headwaters Region from 1982 to 2014 were comprehensively analysed. The annual precipitation data for the Three-River Headwaters Region from ERA5-Land, the Climatic Research Unit, the China Meteorological Forcing Dataset and the Global Land Data Assimilation System (GLDAS) all showed an increasing trend; the annual evapotranspiration data from ERA5-Land, Global Land Data Assimilation System, Global Land Evaporation Amsterdam Model (GLEAM) and Terrestrial Evapotranspiration Dataset across China (TEDC) all showed an increasing trend; and the annual soil water storage data from ERA5-Land, Global Land Data Assimilation System and Global Land Evaporation Amsterdam Model all showed an increasing trend. The annual snowmelt data from ERA5-Land, Global Land Data Assimilation System and SMT-Y datasets all showed a decreasing trend. The annual glacier melt increased in the Yangtze River Headwater Region and Yellow River Headwater Region and decreased in the Lantsang River Headwater Region. The increases in precipitation, evapotranspiration, soil water content and glacial melt, and the decreases in snowfall and snowmelt indicate an accelerated hydrological cycle in the Three-River Headwaters Region over the 1982 to 2014 period. The significant increase in precipitation is the main reason for the significant increase in runoff in the Yangtze River Headwater Region. The increase in precipitation in the Yellow River Headwater Region was less than the sum of the increase in evapotranspiration and soil water storage, resulting in a decreasing trend of runoff in the Yellow River Headwater Region. The increase in precipitation in the Lantsang River Headwater Region was slightly larger than the sum of that in evapotranspiration and soil water storage, and there was an insignificant increase in the runoff in the Lantsang River Headwater Region.

Tree variability limits the detection of nutrient treatment effects on sap flux density in a northern hardwood forest.

The influence of nutrient availability on transpiration is not well understood, in spite of the importance of transpiration to forest water budgets. Soil nutrients have the potential to affect tree water use through indirect effects on leaf area or stomatal conductance. For example, following addition of calcium silicate to a watershed at Hubbard Brook, in New Hampshire, streamflow was reduced for 3 years, which was attributed to a 25% increase in evapotranspiration associated with increased foliar production. The first objective of this study was to quantify the effect of nutrient availability on sap flux density in a nitrogen, phosphorus, and calcium addition experiment in New Hampshire in which tree diameter growth, foliar chemistry, and soil nutrient availability had responded to treatments. We measured sap flux density in American beech (Fagus grandifolia, Ehr.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), white birch (Betula papyrifera Marsh.), or yellow birch (Betula alleghaniensis Britton.) trees, over five years of experiments in five stands distributed across three sites. In 2018, 3 years after a calcium silicate addition, sap flux density averaged 36% higher in trees in the treatment than the control plot, but this effect was not very significant (p = 0.07). Our second objective was to determine whether this failure to detect effects with greater statistical confidence was due to small effect sizes or high variability among trees. We found that tree-to-tree variability was high, with coefficients of variation averaging 39% within treatment plots. Depending on the species and year of the study, the minimum difference in sap flux density detectable with our observed variability ranged from 46% to 352%, for a simple ANOVA. We analyzed other studies reported in the literature that compared tree water use among species or treatments and found detectable differences ranging from 16% to 78%. Future sap flux density studies could benefit from power analyses to guide sampling intensity. Including pretreatment data, in the case of manipulative studies, would also increase statistical power.

Impact of Landuse and Landcover Changes on Hydrological Components of the Oti Sub-Basin of Ghana

Landuse and landcover have over the decades been undergoing changes as a result of natural and human activities. These changes for a given area can be attributed to fluctuations in the infiltration ability of the land, leading to changes in the hydrological cycle of a given catchment area. This research assessed some of the impacts that landuse and landcover changes coupled with climate variations have on the hydrological components of the Oti sub-basin of Ghana using the Soil Water Assessment Tool (SWAT) with ArcGIS® interface for the development of models from which conclusions were drawn. The research incorporated into the SWAT system two landuse and landcover data: 1984 and 2013 which were modeled and evaluated alongside soil, slope and climate dataset. The results from running the model indicated a very significant change in landuse and landcover and a loss of forest cover which has negative effect on the hydrological components of the basin. Also, the rainfall trend analysis gave negative significant values of -2.28 and -2.78 for the two stations located at Zabzugu and Bimbila within the basin. Together, these changes have led to an increase in evapotranspiration (ET) and decrease in surface water, lateral flow and groundwater recharge. This is an indication that climate change impact on the basin is a function of the landuse and landcover changes. There is an urgent need for all stakeholders to help protect the basin from anthropogenic activities such as farming too close to the basin in order to prevent future water availability issues in the basin.

Impacts of land use/cover change on water balance by using the SWAT model in a typical loess hilly watershed of China

Land use/cover change (LUCC) plays a key role in altering surface hydrology and water balance, finally affecting the security and availability of water resources. However, mechanisms underlying LUCC determination of water-balance processes at the basin scale remain unclear. In this study, the Soil and Water Assessment Tool (SWAT) model and partial least squares regression were used to detect the effects of LUCC on hydrology and water components in the Zuli River Basin (ZRB), a typical watershed of the Yellow River Basin. In general, three recommended coefficients (R² and Ens greater than 0.5, and Pbias less than 20%) indicated that the output results of the SWAT model were reliable and that the model was effective for the ZRB. Then, several key findings were obtained. First, LUCC in the ZRB was characterized by a significant increase in forest (21.61%) and settlement (23.52%) and a slight reduction in cropland (–1.35%), resulting in a 4.93% increase in evapotranspiration and a clear decline in surface runoff and water yield by 15.68% and 2.95% at the whole basin scale, respectively. Second, at the sub-basin scale, surface runoff and water yield increased by 14.26%–36.15% and 5.13%–15.55%, respectively, mainly due to settlement increases. Last, partial least squares regression indicated that urbanization was the most significant contributor to runoff change, and evapotranspiration change was mainly driven by forest expansion. These conclusions are significant for understanding the relationship between LUCC and water balance, which can provide meaningful information for managing water resources and the long-term sustainability of such watersheds.

Impact of surface and underground water uses on streamflow in the upper-middle of the Weihe River basin using a modified WetSpa model

Anthropogenic water use activities contribute substantially to natural hydrological processes. However, their effects on distributed hydrological simulations are currently poorly understood due to the lack of observed data on water use. To address this issue, we developed a model by using the Water and Energy Transfer between Soil, Plants, and Atmosphere (WetSpa) with water withdrawal and consumption modules, namely WetSpa-WW. Differently from previous studies roughly estimating water use, the observed withdrawal of surface water and groundwater, as well as industrial, domestic, and agricultural water consumption in sub-basins, were used according to the site-based measurements. This model was applied to the upper and middle reaches of the Weihe River Basin (UMWRB). Results show that: (1) The proposed WetSpa-WW improved simulation efficiency both of streamflow and actual evapotranspiration (AET), e.g., the relative error (RE) of AET decreased from 20.3 % to −6.43 %. (1=2) The RE of streamflow at the outlet of the basin increases from 10.5 % to 15.3 % without considering the spatial distribution of water use among sub-basins. (3) In the period of 2017–2020, the mean water withdrawal stood at 49.64 mm/a over the basin, resulting in a reduction of streamflow by 22.24 mm/a and an increase of actual evapotranspiration by 6.97 mm/a. This study demonstrates a great potential gain available to the distributed hydrological models integrating records of actual water use, rather than more widely used national statistics.

Assessment of Climate Change Impacts for Balancing Transboundary Water Resources Development in the Blue Nile Basin

An assessment of climate impacts in the hydrologic system of the Blue Nile basin is useful for enhancing water management planning and basin-wide policymaking. Climate change adaptation activities predominantly require an understanding of the range of impacts on the water resource. In this study, we assessed climate change impacts on the Blue Nile River using 30-year in situ climate data (1981–2010) and five bias-corrected General Circulation Models (GCMs) for future (2026–2045) climate projections of RCP8.5. Both historical and GCM precipitation projections show inter-annual and spatial variability, with the most significant increases in the rainy season and a significant decrease in the dry season. The results suggest the probability of an increase in total precipitation. The intensity and frequency of future extreme rainfall events will also increase. Moreover, the hydrological model simulation results show a likely increase in total river flow, peak discharges, flood inundation, and evapotranspiration that will lead to a higher risk of floods and droughts in the future. These results suggest that the operation of water storage systems (e.g., the Grand Ethiopian Renaissance Dam) should be optimized for Disaster Risk Reduction (DRR) and irrigation management in addition to their intended purposes in the Nile basin.

Changing Trends in Drought Patterns over the Northeastern United States Using Multiple Large Ensemble Datasets

Abstract Since the infamous extreme drought of the 1960s, the climate of the northeastern United States (NEUS) has generally trended toward warmer and wetter conditions. Nonetheless, there is mounting evidence that short-term droughts will continue to pose a significant risk for this region. To better explore the processes governing events such as these, climate models have adopted more complex representations of the fully coupled atmosphere–land–ocean–sea ice system; however, large uncertainties in future projections still persist, with internal variability necessitating large ensembles to understand trends in both rare and high-impact extreme events such as rapidly developing droughts (a term here that includes flash droughts developing on monthly scales). In this study, seven large ensemble (LE) models are employed to answer the outstanding question: How are the frequency and character of drought in the NEUS changing under a warming climate? We find that most LE models indicate the NEUS will experience a long-term wetting trend with more “extremely wet” months, but also more frequent short-term extreme droughts. These changes are associated with increasing precipitation, atmospheric water demand, and climate variability. We also conclude that discrepant trends in precipitation and evapotranspiration variability will lead to increasing anticorrelation of these variables, which is relevant to the intensification of rapidly developing drought, particularly in the spring season. These changes are associated with an increase in evapotranspiration from plants, brought by an earlier emergence of the growing season and denser vegetation. Significance Statement Droughts are extreme events with the potential to produce considerable social and economic damage. Because droughts emerge slowly and are relatively infrequent, large datasets are needed to study these features. Using multiple climate models, each producing multiple long-duration simulations, along with a novel drought index, we characterize rapidly developing droughts (those flash droughts identifiable from monthly data) and understand their drivers in the northeastern United States. We find that short-term extreme droughts are projected to be more frequent, while rapidly developing droughts will become more intense in the spring season. Intensification of rapidly developing droughts is attributed to differences in patterns of precipitation and evapotranspiration (soil evaporation and plant transpiration), which will be magnified by an extended growing season and an increase in vegetation.

Impacts of Climate and Land-Use Changes on Hydrological Processes of the Source Region of Yellow River, China

Climate variability and land-use change are key factors altering the hydrology of a river basin, which are strongly linked to the availability of water resources and the sustainability of the local ecosystem. This study investigated the combined and individual impacts of land-use changes (LUCs) and climate change (CC) on the hydrological processes in subbasins of the Source Region of the Yellow River (SRYR) through statistical methods and hydrological modeling based on two land-use maps for the period 1990 and 2010, and two climate periods, i.e., 1976–1995 and 1996–2014. The results revealed that the climate is anticipated to be warmer and wetter. Land-use changes were dominated by decreases in sparse grassland. However, the transformation of land-use changes varied spatially within sub-basins. The combined impacts of climate and land-use changes are more noticeable in the Maqu subbasin, where the decrease in runoff reached 18% (32.2 mm) and increase in evapotranspiration (ET) reached 10.4% (34.1 mm), followed by the Tangnaihai and Jimai subbasins. The changes in runoff and ET caused by LUC seemed to be adequate by comparison, and presented a 15.1–19.8% decline in runoff and 21.3–28% increase in ET relative to the totals. Overall, climate change has more influence on hydrological processes in all subbasins of the SRYR than LUC. It is, therefore, considered that the response to changes in hydrological processes in a subbasin can be attributed to changes in individual climate parameters and land-use classes.

Faster increase in evapotranspiration in permafrost-dominated basins in the warming Pan-Arctic

Land evapotranspiration (ET) is a key factor in the hydrological cycle and is particularly sensitive to climate change. In the past few decades, the Pan-Arctic region has witnessed a strong warming trend, causing substantial changes in ground surface conditions. However, it remains poorly understood how ET varies across such a region. Here, we investigated the spatial–temporal changes in ET over six large Pan-Arctic river basins using corrected ET estimates from GLEAM and ERA5-Land during 1981–2020. The 40-year mean annual ET in the Ob, Yenisei, Lena, Kolyma, Yukon, and Mackenzie River basins were approximately 366 mm·yr−1, 271 mm·yr−1, 228 mm·yr−1, 239 mm·yr−1, 278 mm·yr−1, and 295 mm·yr−1, respectively. Climatologically, permafrost-dominated basins tend to have lower ET than those with less permafrost. Temporally, the annual ET in permafrost-dominated basins has increased faster than that in less permafrost-developed basins over the past four decades. This increase is particularly prominent in the Kolyma River basin (completely covered by permafrost), where the significant trend in ET (7.5 mm·decade−1, p < 0.001) is the highest among the six basins. Further analyses show that intensified permafrost thawing is likely the key factor contributing to increased ET in permafrost-dominated basins, as seen from the positive relationship between the thickening in the active layer (ALT) and the change in ET. Under an amplified warming background, ET in permafrost-dominated regions is expected to continue to increase. The results reported in this study improve our understanding of the variations in ET and the associated mechanisms in the changing Arctic.

Climate fluctuation impacts in Astronium urundeuva (M. Allemão) Engl. silvicultural characters in the Brazilian Cerrado

Currently, mankind is responsible for changing our planet’s conditions. These changes are usually catastrophic, and yet, mankind does not develop preventative strategies to reduce their impacts. However, a species present in the Brazilian Cerrado, Astronium urundeuva, can be very economically logged and has a known landscape distribution, but lacks information regarding the impacts of climate change on its silviculture. This research aimed to verify A. urundeuva’s silvicultural behavior under current environmental conditions. Progenies from three populations (Cerrado and Atlantic Forest/Cerrado transition) were measured for silvicultural characters: height (HT) and diameter at breast height (DBH), in 2019. Climatic data (temperature, precipitation, evapotranspiration and soil available water, averages and accumulated) were also measured between 1996 and 2018. Descriptive and sequential water balance analysis, descriptive statistics, collinearity tests and a multiple linear regression were performed. There was water deficit in all years (−12.7 mm) researched, which showed an irregular rainfall distribution in Selvíria-MS, concentrated mostly in summer. Average HT ranged from 8.02 m to 10.69 m, while average DBH ranged from 0.10 m to 0.12 m, with high variability (CVs between 21.99% and 34.77%). There was significant correlation between HT, DBH, , and and between , and , which highlighted the importance of water availability . Multiple linear regression showed has a direct and negative relationship with silvicultural characters, implying productivity losses while evapotranspiration increases. Even though it is not a typical Cerrado species, A. urundeuva may have adapted to phytogeographic domain conditions, with slow growth due to water deficit for its survival, considering that, in Brazil, climate change has resulted from annual variations.

Estimation of Water Balance for Anticipated Land Use in the Potohar Plateau of the Indus Basin Using SWAT

Land Use/Land Cover (LU/LC) change is among the dominant driving factors that directly influence water balance by transforming hydrological responses. Consequently, a thorough comprehension of its impacts is imperative for sustainable water resource planning and development, notably in developing worlds such as Pakistan, where agriculture is a major livelihood. This research intends to assess the continuing changes in LU/LC and evaluate their probable repercussions on the hydrological regime of the Potohar Plateau. The maximum likelihood classification (MLC) algorithm for land use classification of the high-resolution satellite imageries, the Cellular-Automata Markov Chain Model (CA-MCM) for the projection of LU/LC maps, and the Soil and Water Assessment Tool (SWAT) in tandem with SWAT-CUP for hydrological modeling were employed in this research. The high-resolution climatic dataset (10 × 10 km) was used in SWAT. The LU/LC analysis revealed a continual propagation of agricultural and built-up lands at the detriment of forest and barren land during the last three decades, which is anticipated to continue in the future, too. Hydrological model calibrations and validations were performed on multi-basins, and the performance was evaluated using different statistical coefficients, e.g., the coefficient of determination (R2), Nash–Sutcliffe Efficiency (NSE), Kling–Gupta Efficiency (KGE), and Percent Bias (PBIAS). The results yielded that the model performed very well and demonstrated the model’s robustness in reproducing the flow regime. The water balance study revealed that the anticipated LU/LC changes are projected to decrease the mean annual surface runoff, water yield, and streamflow due to an increase in percolation, lateral flow, sub-surface flow, and evapotranspiration. More significant variations of the water balance components were observed at the sub-basin level, owing to the heterogeneous spatial distribution of LU/LC, than at the basin level. The outcome of this study will provide pragmatic details to legislative bodies to develop land and water management ameliorative strategies to harness hydrological changes sustainably.